1. Field of the Invention
The present invention relates to a swinging leg pendulum movement aid for walking and an assistance force control method. This invention is used by a person with decreased walking ability or the like, and promotes walking movement using his own muscle strength by supporting walking movement with a small force. For example, by increasing the walking speed, the invention is able to effectively suppress a decrease in muscle strength. Meanwhile, when keeping a fixed walking speed, for example, the invention is able to assist longer distance walking by walking being supported for a long period with a lower amount of energy.
2. Description of the Related Art
From the past, to support walking of a physically disabled person or elderly person with low muscle strength, assistive devices to be worn such as those disclosed in U.S. Publication No. US 2008/0234608 and U.S. Publication No. US 2011/0218466 have been proposed.
Meanwhile, the assistive devices of the conventional structure noted in these US 2008/0234608 and US 2011/0218466 are exoskeleton type assistive devices, in which the exoskeleton is made from a rigid arm or frame and is worn along the user's body. By the exoskeleton being driven by a motor at the joints, the user's leg is made to move together with the exoskeleton arm.
However, the conventional assistive devices which used this kind of rigid exoskeleton all aided the muscle strength of the leg on the grounding side. The leg on the grounding side which requires high muscle strength so as to support the body weight or the like with two legged walking which repeats alternately grounding and floating in relation to the ground. Because of that, there was the problem that it was difficult to avoid the device from becoming larger or heavier because a large output was required.
In fact, with the conventional assistive devices that aid the muscle strength with a large output assistance for the grounding side leg muscle strength, as a result of being able to do this with little burden on the muscle strength of the user himself, there was the problem that it was difficult to expect an effect of developing the user's own muscle strength and suppressing a decrease in muscle strength. Because of that, particularly with a person with decreased walking ability referred to as locomotive syndrome or the like for which there is a walking disability for a reason such as aging or the like, but does not go so far as being unable to walk, even when using an assistive device which performs muscle strength assistance to the grounding leg using a conventional rigid skeleton structure, it is difficult to expect maintaining or improvement of walking ability, and this was not necessarily effective for inhibiting a shift toward a serious walking disability to the point of being unable to stand and walk.
Also, with a conventional rigid exoskeleton structure assistive device, if it did not match the user's physical build correctly, or it was not worn properly, there was also the risk of excessive force being applied to the user's joints or the like during exercise due to the rigidity of the exoskeleton.
In addition, from the fact that the movement of the user's joints is constrained by the rigid exoskeleton, for example when there is a disturbance such as external force or the like in the horizontal direction on the user, there was also the risk of obstruction to movement to prevent falling down by spontaneous reaction of the user, leading to falling over.